Regenerative heat exchanger



March 29, 1966 8 Sheets-Sheet 1 Original Filed Feb. 11, 1963 INVENTORWILLIAM A. MORTON ATTORNEY March 29, 1966 w. A. M'ORTQI'Q 3,242,976

REGENERATIVE HEAT EXCHANGER Original Filed Feb. 11, 1963 8 Sheets-Sheet2 l "I I 9 I II N I I 8 N I o] co LI"-"'" 3 co I i I.-- I

'l I I 3 II I N] I I Iii. IIIU I I I", N ww ooJ I I g CD vifiliiiiliififif P I LL. NI 9 v I I I i IZ I::::::::: I ZIEIHI 5%, v I II II 0 I I g I I I? 1H m INVENTOR WILLIAM A. MORTON ATTORNEY 8Sheets-Sheet 5 INVENTOR WELLIAM A. MORTON ATTORNEY W. A. MORTONREGENERATIVE HEAT EXCHANGER March 29, 1966 Original Filed Feb. 11, 1963y y WM March 29, 1966 w. A. MORTQN 3,242,976

REGENERATIVE HEAT EXGHANGER 8 Sheets-Sheet 4 Original Filed Feb. 11,1963 J3EE?! JILIJILFJQEL- I II luglglglglgl I 5 o INVENTOR WILLIAM A.MORTON ATTORNEY March 29, 1966 w. A. MORTON 3,242,976

REGENERATIVE HEAT EXCHANGER Original Filed Feb. 11, 1963 8 Sheets-Sheet5 ATTORNEY March 29, 1966 w. A. MORTOQ 3,242,976

REGENERATIVE HEAT EXCHANGER Original Filed Feb. 11, 1965 8 sheets-sheet6 INVENTOR WILLIAM A. MORTON WW M ATTORNEY March 29, 1966 w. A. MORTONREGENERATIVE HEAT EXCHANGER 8 Sheets-Sheet 7 Original Filed Feb. 11,1963 INVENTOR. WILLIAM A. MORTON BY do 6 W ATTORNEY March 29, 1966 i w.A. MORTION 3,242,976

REGENERATIVE HEAT EXCHANGER 8 Sheets-Sheet 8 Original Filed Feb. 11,1963 BY WM ATTORNEY United States Patent The present invention relatesto regenerative heat exchangers and, more particularly, to regenerativeheat exchangers utilizing the heat from the exhaust gases of a furnacefor preheating combustion air supplied to the furnace.

In furnaces of the type utilized for steelmaking and other applicationswherein large amounts of heat at high temperatures are required, it ishighly desirable to utilize the heat available in the exhaust gases forpreheating the air supplied for combustion in the furnace in order toimprove the efficiency and, consequently, reduce the operating costs.

One system presently in wide use for this purpose utilizes a pair ofheat exchangers having regenerative material therein. Air for combustionis drawn into the furnace through one of the exchangers and the exhaustgases are passed out through the other exchanger, causing theregenerative material therein to be heated. The flow is then reversedwith combustion air being drawn in through the exchanger which has justbeen heated by the exhaust gases and the exhaust gases passing outthrough the other exchanger heating it up. In the usual application, theflow is reversed about every fifteen minutes or so. This system has manydisadvantages, i.e., high initial cost and low efficiency, but the maindisadvantages are first the need for two rather than a single heatexchanger and the further disadvantage that the temperature of thepreheated air is not constant, but gradually diminishes as the preheatchamber cools.

Another system used is a rotary-type heat exchanger having longitudinalflues therein which are heated by the exhaust gases passing through andthen give up this heat to combustion air passing through as theexchanger is rotated. The exchanger is generally constructed of an alloycapable of withstanding high temperatures but, as yet, these types ofexchangers are limited to around 1500 degrees F. whereas in manyapplications much higher temperatures are desirable.

Therefore, it is an object of the present invention to provide a new andimproved regenerative-type heat exchanger which eliminates or greatlyreduces one or more of the disadvantages of the aforementioned systems.

More specifically, it is an object of the present invention to provide anew and improved regenerative heat exchanger of the rotary type havinglongitudinal passages therein constructed with a regenerative materialof a relfractory type wherein the exhaust gases from the furnace movethrough the passages giving up heat which is later transferred topreheat combustion air moving through the passages as the exchangerrotates.

, Another object of the present invention is to provide a new andimproved regenerative heat exchanger of the type described wherein thepassages carrying waste gases 1 are purged of these waste gase duringrotation, these "waste gases being prevented from returning to thefurnace, and those passages carrying combustion air which has beenheated are purged of this heated air so it is not lost to the atmospherebut is channeled back so it may be supplied to the furnace or deviceassociated with the regenerative heat exchanger. i

The present invention has for another object the provision of a new andimproved regenerative heat exchanger of the type described wherein wastegases having tem- 3,242,976 Patented Mar. 29, 1966 peratures ofapproximately 2500 F. may be utilized for preheating air to temperatureshigher than with previous practice, whereby exchangers are capable ofbeing utilized in high temperature applications not possible with thetypes previously mentioned.

Yet another object of the present invention is to provide a new andimproved regenerative exchanger of the type described which is capableof heating large amounts of combustion air to a relatively constanttemperature.

A further object of the present invention is to provide a new andimproved regenerative heat exchanger of the type described having aninsulated drum rotatable about either a horizontal or vertical axiscontaining a plurality of fluid passages constructed of a refractorymaterial, in juxtaposition to non-rotating end plenum chambers anddivision walls positioned to sealingly engage the ends of the drum alonga chord thereof to direct the flow of exhaust gases through one set ofpassages, and air to be preheated through another set of passages in amanner to effect a heat exchange between the regenerator materials andthe fluids without appreciable mixing of the fluids and withoutappreciable loss of heat to the atmosphere.

A still further object of the present invention is to provide a new andimproved regenerative heat exchanger of the type described in thepreceding paragraph wherein new and improved means are provided forsupporting the end bafiies so as to maintain their relatively sealedengagement with the ends of the drum as the drum expands and contractsduring heating and cooling.

Yet another object of the present invention is to pro vide a new andimproved regenerative heat exchanger of the type described which issimple and economical of construction and operation, highly efficient ineffecting heat transfer, relatively small in size and easy to maintain.

Further objects and advantages of the present invention will becomeapparent as the following description proceeds and the features ofnovelty which characterize the invention will be pointed out withparticularity in the claims annexed to and forming a .part of thisspecification.

The foregoing and other objects and advantages of the present inventionare accomplished by the provision of a new and improved regenerativeheat exchanger for effecting a heat transfer between fluids whereinthere is provided an insulated rotating drum having a plurality ofseparate longitudinal passages therein constructed of a refractorymaterial capable of withstanding extremely high temperatures. The drumis positioned to rotate about its longitudinal axis and there areprovided at the opposed ends of the drum nonrotating baffies, each inperipheral sealing engagement with an end of the rotating drum. Each ofthe baffles is provided with an inlet and an outlet which are separatedby a division wall or center post. The inlet of one bafile is positionedto be in continual communication with the outlet of the other bafllethrough a plurality of the passages in the drum as it rotates, thusproviding for the movement of gases into and out of the heat exchanger.The inlet of the other baflle is in continual communication with theoutlet of the one baffle through a plurality of passages in the drum asit rotates, thus likewise providing for the movement of gases throughthe exchanger in the opposite direction. Combustion air to be preheatedpasses through the inlet of one bafile and the passages of the rotatingdrum which have previously been heated by the passage of exhaust gasestherethrough, thus effecting a heat exchange between the gases topreheat the combustion air.

The center posts or division walls of the bames are positioned inparallel relation to one another at opposed ends of the drum. Each ofthe posts is provided with passage means; the passage means in one ofthe bafiles being in communication with the air inlet thereof and aplurality of the passages in the rotating drum, and the passage means inthe other baffle being in communication with the waste gas inlet thereofand a plurality of passages in the rotating drum. Each of the centerposts is provided with means for purging the passages in the rotatingdrum as they pass in line with the posts, the purging means in eachcenter post being in communication with the passage means in theopposite posts so that the purging fluid will be directed through thepassages in the drum and out the passage means in the posts. In one casethe purging means prevents Waste gases from being returned to thefurnace and in the other case prevents heated combustion air from beinglost'to atmosphere.

ther features of the invention include means which support one ofthebattles so that it can move longitudinally with the drum in order tomaintain the peripheral sealing engagement between the end of the drumand the baflie-s 'as the drum elongates and contracts due to heating andcooling. Additionally, new and improved rotary seals areprovided-between the drum ends and the baflies so that gases within thedrum do not escape therefrom in excessive amounts. Also the ends of thefluid passages in the rotating drum are tapered in order to reduceleakage between adjacent passages while providing minimum clearancebetween the baflies and the drum.

For a better understanding of the present invention, reference may behad to the accompanying drawings wherein:

FIG. 1 is a top plan view of a furnace system employing a new andimproved regenerative heat exchanger constructed in accordance with thefeatures of the present invention;

FIG. 2 is a side elevational view of the apparatus of FIG. 1;

FIG. 3 is a somewhat enlarged sectional view taken substantially alongline 33 of FIG. 1;

FIG. 4 is a sectional view taken substantially along line 44 of FIG. 3,assuming that FIG. 3 shows the complete structure;

FIG. 5 is a sectional view taken substantially along line 55 of FIG. 3,again assuming that FIG. 3 shows the complete structure;

FIG. 6 is a somewhat enlarged sectional view taken substantially along'line 6-6 of FIG. 2;

FIG. 7 is an enlarged sectional view taken substantially along line 77of FIG. 2;

FIG. 8 is an enlarged sectional view taken substantially along line 8-8of FIG. 2;

FIG. 9 is a sectional view taken substantially along line 9-9 of FIG. 7,assuming that FIG. 7 shows the complete structure;

FIG. 10 is a sectional view taken substantially along line 1010 of FIG.8, assuming that FIG. 8 shows the complete structure;

FIG. 11 is an enlarged fragmentary sectional View taken substantiallyalong line 1111 of FIG. 2;

FIG. 12 is an elevational view, with certain portions cut away,illustrating another embodiment of the present invention;

FIG. 13 is a sectional view taken on line 13-13 of FIG. 12, assumingthat FIG. 12 shows the complete structure; and

FIG. 14 is asectional view taken on line 1414 of FIG. 12, again assumingthat FIG. 12 shows the complete structure.

Referring now to the drawings, there is illustrated a furnace system 12including the regenerative heat exchanger 13 which is constructed inaccordance with the features of the present invention. In a typicalapplication, the exchanger 13 is utilized for preheating combustion airsupplied to a high temperature furnace 14 through an inlet duct 15. Thehigh temperature waste gases or products ofcombustionfrom the furnace 14pass from the furnace through an outlet duct 16 into the exchanger 13whereby heat is extracted therefrom for use in preheating the combustionair supplied to the furnace through inlet duct 15.

Essentially, the heat exchanger 13 comprises a rotating drum 18containing a heat regenerative material which is supported from asuitable structure such as the base 20 (FIGS. 2, 6, 7 and 8) forrotation about a horizontally disposed longitudinal axis. An end baflie22 is positioned in peripheral sealing engagement with the end of therotating drum 18 adjacent the furnace 14 for directing preheatedcombustion air from the drum to the inlet duct 15 of the furnace and fordirecting the waste gases from the outlet duct 16 of the furnace intothe rotating drum 18. At the other end of the drum 18 there is providedanother end baffle 24 which is positioned in peripheral sealingengagement with the corresponding drum end for directing combustion airto be preheated into the drum and directing waste gases from the drum toan exhaust stack 25.

The drum 18 is constructed of an outer cylindrical shell 26 of steelplate and is provided with an internal lining 28 of insulating materialfor preventing the steel shell from overheating due to the extremelyhigh temperatures within the drum. The lining 28 extends almost theentire length of the shell stopping short of the ends as shown in FIG.3. Angle flanges 30 and 32 .are provided at the ends of the drum forstiffening the shell or drum 18 and providing support for radiallydisposed annular end face plates 34 and 36 which are secured thereto.

In order to provide'for the passage of combustion air and Waste gasesthrough the drum and to preheat the combustion air and extract heat fromthe waste gases, drum 18 is provided with a plurality of separatelongitudinal fluid passages 38. The walls of these passages are formedof a refractory material, such as fire brick 40, having a high magnesiacontent in order to withstand temperatures as high as 3000 F. The firebricks are provided with V-shaped edges (FIGS. 4 and 5) and are arrangedto form passages of square or rectangular cross section as shown inFIGS. 4 and 5 of the drawings with the joints staggered longitudinally,as shown in FIG. 3. The individual bricks are cemented together with arefractory cement and, thus, form an integral structure within the drum18. The central passages formed by the fire brick are not utilized, aswill become apparent from the ensuing description, and are plugged atthe ends with plugs 42 of refractory material to prevent fluid passagethrough these central passages. It should be noted that the V-shapededges of the fire brick 40 dovetail together nicely to provide a passagestructure that is strong and easy to construct. Additionally, the firebricks at both ends are provided with V-shaped ends 40a which lie in aplane with end face plates 34 and 36 and reduce the friction of theentering air or waste gas.

For the purpose of supporting the fire brick structure within the drum18, the structure is surrounded by a refractory lining 44 which ispreferably of a castable type refractory material. The lining 44 servesto securely hold the fire brick structure and the insulation lining 28in place Within the shell 26 of drum 18 to rotate therewith. It shouldbe noted from FIG. 3 that the lining 44 is provided with end flanges 44awhich extend outwardly to engage the interior of the shell 26 betweenthe ends of the insulation lining 28 and the inside faces of the endface plates 34 and 36. This construction serves to bond the wholeinternal structure of the drum tightly within the shell 26. The outerend faces 44b of the lining '44 are flush with the outer faces of theface plates 34 and 36 in order to provide smooth surfaces which are ininterfacing relation with the end baffles 22 and 24.

To support the drum 18 for rotation, itis provided with a plurality ofannular tracks 46,48 and 50 which are spaced appropriately along thelength of the drum. These tracks additionally serve-as stiffeners forthe dmrn and the number of tracks needed depends on the thickness of theshell 26, the length of the drum and its weight. Tracks 46 and 48 havesufiicient width to permit substantial movement of the drum withlongitudinal expansion and contraction thereof.

Each of the tracks is supported for rotation on two pairs of rollers 52(FIG. 6) and each pair of rollers is carried by a bracket 54 which ispivotally mounted on a hinge bracket 56 secured to the frame 20. Thebrackets 56 can be adjusted inwardly or outwardly on the frame tocompensate for the wear on the tracks and rollers. The track 50, whichis closest to the furnace end of the drum 18, is provided with a pair ofsmall annular flanges 50a which form a channel-shaped recess 0n theouter surface of the track in which the rollers 52 ride, thuseffectively anchoring the furnace end of the drum 18 and requiringexpansion to be taken care of by movement of the stack end of the drum.Thus, the tracks 46 and 48 are not provided with flanges therebyaccommodating such expansion and contraction of the drum 18 as it isheated and cooled.

For the purpose of rotating the drum 18 in typical applications (asindicated by the arrows in FIGS. 1, 2, .6, 7 and 8) there is provided anelectric motor 56 which is drivingly connected to a right angle-typegear reducer 58 having an output shaft 58a extending parallel to thelongitudinal axis of the drum. The gear reducer 58 is coupled to themotor 56 through an adjustable gear reducer 60 (FIG. 6) having a controlhandle 60a for varying the speed ratio thereof in order to rotate thedrum 18 at the desired speed. The output shaft 58a is connected by anysuitable means, such as a chain or belt drive 61, to a shaft 62 which isjournaled in the brackets 57 and extends longitudinally parallel withthe drum 18. The shaft 62 is drivingly connected to the rollers 52 bymeans of chain, belt or other suitable drives 64 to rotate the rollers52 and thus drive the drum.

The furnace end baffle 22 (FIGS. 8 and comprises an outer cylindricalshell 66 of a diameter equal to the shell 26 and a circular back plate68 welded thereto. The circumferential edge of the shell 66 facing thedrum is provided with an angle ring stiffener 78 to which is attached anannular face plate 72 of the same dimensions as and positioned to facethe face plate 34- on the rotating drum 18. Between these two faceplates there is provided a sealing ring 74 which is constructed ofasbestos or other material having heat resistant qualities and arelatively low coefficient of friction. The seal ring 74 is attached tothe face plate 72 and the baffle 22 is positioned so that the outer faceof the seal ring closely abuts the face plate 34 on the drum 18, thusproviding a rotary seal between the drum and baffles which is capable ofwithstanding high temperatures. Since the furnace end of drum 18 iseffectively fixed with respect to longitudinal movement, the baffle 22is fixedly supported in position by means of side braces 76 and the endbrace 78 which are attached to the frame 20.

The interior of the bafile 22 is lined with a refractory material 80which is preferably of a castable-type refractory material and isintegrally cast within the b aille to form an outlet cavity 82 and aninlet cavity 84(FIG. 8) which are separated by a center post 86. Thesecavities are generally semicircular in cross section and each is incontinual communication with a little less than half of the passages 38in the rotating drum; the few remaining passages in the drum beingpositioned in front of the center post 86. The outlet cavity 82 isprovided with a rearwardly extending outlet duct 88 which is also linedwith the refractory material 80 and is connected to the inlet duct ofthe furnace 14 by means of a duct 90 which is also lined with refractorymaterial. The inlet cavity 84 is provided with an enlarged inlet duct 92also lined with the refractory material 80 which is connected to arefractory lined duct 94 attached to the outlet duct 16 of the furnace14. The larger furnace outlet duct 16 and 6 ducts 92 and 94, as comparedwith furnace inlet duct 15 and ducts 88 and 91), is to take care of thevariation in volume with heating of the air or gases involved due totemperature.

For purging purposes, the center post 86 of furnace end baflle 22 isprovided with a plurality of spaced-apart purging nozzles 96 which arepositioned in a vertical center line above the axis of drum rotation andare directed to blow streams of clean air or other gas into the passages38 of the drum which have just been carrying waste gases as they pass infront of the nozzles as the drum rotates. This purging air is exhaustedat the other end into the waste or exhaust gas duct leading to stack 25,as described hereinafter. Diametrically opposite to the nozzles 96 thereare provided a plurality of purged gas receiving passageways 98. Thesepassageways are of L shape and positioned to receive purging gasdirected into the passages 38 from the other end of the drum which havejust been carrying waste gases and are in communication with the cavity84 so that these waste gases do not return to the furnace but mix withthe waste gases coming from the furnace through duct 16.

Similarly, the stack end baffle 24 (FIGS. 7 and 9) has an outercylindrical shell 108 of a diameter equal to that of shell 26 of thedrum 18 and a back plate 102 joined thereto. The periphery of the shellfacing the drum is provided with a stiffening angle ring 104 and anannular face plate 106 of dimensions equal to the stack end face plate36 of the drum 18. There is also provided a sealing ring 108 similar tothe ring 74 for effecting a rotary seal between the drum 18 and thebafiie 24.

In order to maintain a tight seal with the stack end of drum 18 as itexpands and contracts, the stack end baffle 24 is supported on a rollingcradle 11!) having guide rollers 112 which roll on angle tracks 114provided on the base 20. The baffle is attached to the cradle by a pairof side braces 116 and an end brace 118 which maintain the stack baffle24 in a vertical plane as it moves horizontally with the cradle 110.Means such as a pair of tension springs 120 which are connected to theframe 20 and the side braces 116 may be provided for continually biasingthe bafile 24 toward the drum and for maintaining the cradle centered onthe tracks. Thus, the rotary seal comprising element 108 between thebaffie 24 and the drum 18 is continuously maintained regardless of theexpansion or contraction of the drum as it is heated or cooled.

The interior of the bafile 24 is lined with a refractory material 122which is preferably of the castable type and is molded to form an inletcavity 124 and outlet cavity 126 which are separated by a center post128. These cavities are also generally semicircular in cross section andeach is continually in communication with a little less than half of thepassages 38 in the rotating drum; the few remaining passages in the drumbeing positioned in front of the center post 128.

The cavity 124 is provided with an extended inlet duct 130 which islined with the refractory material 122 and connected to a source ofcombustion air 132 by means of a slip joint 134 in order to accommodatethe movement of the baffle. The cavity 126 is provided with an extendedoutlet duct 136 lined with the refractory material 122 and connected tothe exhaust stack 25 by means of a duct 138 and slip joint connection140.

The center post 128 of stack end bafile 24 is provide with a pluralityof purgenozzles 142 which are positioned directly opposite the L-shapedpassageways 98 in the center post 86 of the opposed furnace end baffle22 in order that the purging air from these nozzles will pass throughthe passages 38 in the rotating drum which have just been carrying wastegases to purge them of these waste gases and prevent these gases fromentering the furnace. To this end these purged waste gases enter thepassageways 98 and flow into the cavity 84 and eventually out theexhaust stack 25. L-shaped passageways 144 are provided in the centerpost 128 and are aligned oppo- 3,242, are

site the purging nozzles 96 in the opposite furnace end baffle 22 inorder to receive the purging gas from these nozzles through the passages38 in the drum 18 which have been carrying clean inlet air which hasbeen heated and is now trapped between posts 86 and 128. In order not towaste the heat in this trapped air, passageways 144 are in communicationwith the inlet cavity 128 in order to return the heated combustion airinto the combustion air leading to the furnace.

In operation, combustion air to be preheated passes through the inletduct 130 into the inlet 124 of the stack end bafiie 24. The air thenmoves down the passages 38 of the rotating drum which are at elevatedtemperatures because of the waste gases of high temperatures which havejust previously passed therethrough. The fire brick 40 comprising thewalls of the passages 38 acts as a regenerator in that it accepts andholds heat given up by the waste gases and then gives up this heat tothe combustion air.

The preheated combustion air from the drum passages 38 then passes intothe outlet cavity 82 of the furnace baflle 22 and into the furnace 14through the outlet duct 88, duct 90 and inlet furnace duct 15. Hightemperature waste gases, the products of combustion of the furnace, passfrom the furnace through the outlet duct 16, duct 94, and inlet duct 92into the inlet cavity 84 of the furnace end baffie 22. These hightemperature gases then pass through the passages 38 of the rotating drumin the opposite direction to the flow of combustion air through thepassages causing the passage walls to heat up and, consequently,lowering the temperature of these gases as they reach the end of thedrum 18 and enter the cavity 126 in the stack end baffle 24. The heatgiven up by the waste gases in the passages 38 is stored in therefractory fire brick 40 and is transferred to the combustion airpassing through the passages in the other direction. The waste gases inthe outlet cavity 126 after giving up heat in the passages 38 then passthrough the outlet duct 136, duct 138 to the stack .25. Thus, a greatamount of heat available from the waste gases, which would otherwise beexhausted to the stack'25, is utilized to preheat the combustion airentering with a consequently resulting higher efficiency and loweroperating cost for the furnace. The general direction of air flow isshown by the arrows in FIG. 1.

The center posts 86 and 128 serve as seals dividing the hot and coldsides of the drum and prevent any appreciable dilution of the combustionair with Waste gases or the loss of heat by diverting hot combustion airto the stack. The purging nozzles 96 and 142 introduce a small quantityof high velocity air down the passages 38 as they rotate in front of thenozzles 96 and 142. This air is of higher pressure than either the wastegases or combustion air and, thus provides an effective air seal forpreventing intermixing. The passageways 98 and 144 are positionedopposite these nozzles in the respective center posts and are vented tothe cavities 84 and 126, respectively. Thus, with respect to purgingnozzles 142, which cause purging air to pass through passages 38 whichhave just been carrying waste gases, they force these waste gasestrapped in these passageways between posts 86 and 128 into L-shapedpassages 98 and then into cavity 84, which is in the waste gas side ofthe drum, and out of the stack 25 without intermixing or diluting thefresh combustion air. With respect to purging nozzles 96, they causepurging air to pass through passageways 38 which have been carryingclean combustion air and which have heated combustion air trappedtherein between posts 86 and 128. So that the heat in this air is notlost to atmosphere, it is received by L-shaped passageways 144 and ledinto cavity 128 sov as to mingle with incoming combustion air to beheated by the hot walls of passageways 38.

During each rotation of the drum, each ofthe passages 38 therein hashigh temperature waste gases passed therethrough causing the walls toabsorb heat. As these passages move in front of the purging nozzles 142,the waste gases contained therein are diverted by passageways ?8 intothe waste gases entering cavity 84. After this, fresh combustion air ispassed through these purged passageways 38 which give up their heat topreheat this combustion air.

In this manner the passages 38 are continually purged either of wastegases diverted to the stack, or heated combustion air which is saved byreturning it to the combustion air supply as the drum 18 rotates. Moreover, since the drum is insulated and the passages are constructed ofrefractory material rather than an alloy, temperatures as high as 3000"F. can be maintained. Additionally, only a single drum is needed and thetemperature of the preheated air is relatively constant once equilibriumis attained. The drum is supported for rotation by external tracks withno center shaft being required and the speed of the drum can be adjustedas desired. Moreover, the V-shaped' ends 40a greatly reduce any frictionbetween the drum 18 and the bafiies 22 and 24 While providing a goodfluid seal therebetween.

When the unit is fired up, the drum will expand and this expansion isreadily taken care of by the supporting rollers and the movable bafiies24 with no loss in sealing efliciency at the ends of the drum as theseal between the drum and the end baffles is constantly maintainedregardless of whether the drum is expanding or contracting in length.

Referring now to FIGS. 12, 13, and 14 of the drawings, there isillustrated another embodiment of the present invention wherein avertical arrangement of a furnace system including a furnace and rotaryheat exchanger is illustrated. The corresponding parts of FIGS. 12, 13and 14 are designated by the same reference numerals as in the precedingembodiment. For the purpose of providing support for the furnace 14which, in FIG. 12 of the drawings, is illustrated as being the topmostunit in the vertical arrangement of the system, there is provided aplatform 150. Suitable means 151 are illustrated as securing the furnace14 to the platform 150.

The regenerative heat exchanger is designated as 13' in FIGS. 12 to 14of the drawings. This heat exchanger 13 may be substantially identicalwith the regenerative heat exchanger 13described above, and thecorrespond ing parts thereof are designated by the same referencenumerals as in the preceding drawings. The relationship of the upper endof the heat exchanger 13' to the end baffle 22 is identical with thatpreviously described, and the connections between the furnace 14 and theend baffle 22 are also identical with those previously described and aredesignated by the same reference numerals.

It will be appreciated that since the drum 18' of heat exchanger 13' isvertically disposed, the annular tracks 46, 48 and 50 are no longernecessary and are eliminated. Whether the drum 18' is mounted verticallyor horizontally, however, expansion and contraction thereof will stillresult. Consequently, provision must be made to accommodate suchexpansion and contraction. In the embodiment previously described, thefurnace 14 was fixed as was the baffle 22, and expansion and contractionof drum 18 relative to the other baffie 24 was required. In

the arrangement disclosed in FIG. 12, the end 'bafile 24 is secured to astationary supporting structure. Consequently, relative movement betweenthe upper end of the drum 18 and the associated parts including thefurnace 14 and the bafiie 22 must be provided. To this end the platformis supported on suitable adjustable supports 153 which might be in thenature of jacks ,or the like. With this arrangement the furnace 14 andthe baffle 22, which may be connected thereto, can be raised or loweredas the expansion of the drum 18 requires. It will be appreciated thatsuch adjustment of the supports 153 may be automatically made inresponse to suitable control means or might be manually adjusted. Itwill be appreciated that once steady state operating conditions arereached, the length of drum 18' remains constant and supports 153 willbe adjusted to raise furnace 14' to give the desired clearance when theunit has initially warmed up.

To support the drum 18' for rotation, there is provided at the lower endthereof an annular platform 154 which is secured to the shell 26 of thedrum 18' by a multitude of brace means generally designated at 155. Theannular platform 154 and, consequently, the drum 18' secured thereto aresupported for rotation on a plurality of supporting and driving rollers156 mounted for rotation on suitable supports 157 spaced around theplatform 154, as best shown in FIG. 13 of the drawings, and in turnsupported on a suitable supporting structure or framework 158.Preferably the rollers are adjustable to assure vertical alignment ofthe drum 18'. A suitable prime mover, generally designated at 160,through gear reduction means 161 and drive means 162, 163 and 164,drives some or all of the rollers 156 at the desired speed of rotationof the drum 18'. As illustrated in FIG. 13 of the drawings, two of therollers on diametrically opposed sides of the drum are driven by theprime mover 160 and are driving as well as supporting rollers.

To provide the desired support for the refractory structure containedwithin the shell 26 of drum 18', such as the insulating lining 28, therefractory lining 44 and the fire brick 40 defining the longitudinalfluid passageways 38, some modification in the lower end of the drum 18'is required as contrasted with that of the horizontal arrangementpreviously described. As best shown inFIG. 12 of the drawings, an archedconstruction, generally designated at 165, is provided to support thedownward forces exerted by the center portion of the refractory heatexchange material. This arched construction 165 still insures that thepassageways 38 through the heat exchanger are permitted to connect withthe baffle cavities 124' and 126 defined in lower end baflle 24. Thebaf- :fle 24 is very similar to the baffle 24 described above, but sinceit is supported on the end thereof an inlet opening 167 leading to thecavity 124' is connected to the inlet duct 130 (not shown). Similarly,the cavity 126' is provided with anoutlet opening 168 connected to theoutlet duct 136 (not shown). The cavities 124' and 126 are lined withthe refractory material 122' identical with that lining the cavities inbaffle 24 previously described. The center post 128' of the end baflie24 is provided with a plurality ofpurge nozzles 142 and the L-shapedpassage way 144 previously described.

In view of the detailed description included above, the operation of thesystem disclosed in FIGS. 12, 13'and 14 will be readily understoodbythose skilled in the art and no furthe rldiscussion is includedherewith.

While there have been illustrated and described several embodiments ofthe present invention, it' will be'appreciated that numerous changes andmodifications will occur to those skilled in the art, and it is intendedin the appended claims to cover all those changes and modifications asfall within the true spirit and scope of the present invention.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

1. A regenerative heat exchanger for effecting a heat transfer betweenfluids of different temperatures, comprising a rotating drum containinga plurality of separate longitudinal fluid passages constructed ofrefractory material, means for rotating said drum, a pair of opposed endbaffles, each in peripheral sealing engagement with an end of said drum,each of said baffles having an inlet and an outlet separated by a centerpost, the inlet of one baflle positioned to be in continualcommunication with the outlet of the other baflle through a plurality ofsaid said fluid passages and the inlet of said other bafiie positionedto be in continual communication with the outlet of said one balflethrough a plurality of said fluid passages as the drum is rotated, saidcenter posts positioned parallel to each other and each having passagemeans defined therein, said passage means in one of said baflles beingin communication with the inlet thereof and a plurality of fluidpassages in said drum, said passage means in the other of said bafilesbeing in communication with the inlet thereof and a plurality of fluidpassages in said drum, and fluid passage purging means carried in eachpost, said purging means in each post positioned opposite said passagemeans in the other post for purging a plurality of fluid passages insaid drum.

2. Apparatus as defined in claim 1 wherein said purging means include aplurality of nozzles positioned to direct a high-velocity flow ofpurging fluid into said passages as they pass in front of said nozzlesduring rotation of the drum.

3. A regenerative heat exchanger for effecting a heat transfer betweenfluids of different temperatures, comprising a rotating drum ofregenerative material having a plurality of noncommunicating fluidpassages extending parallel to the axis of rotation of said drum, meansfor rotating said drum, a first end baffle in peripheral sealingengagement with one end of said rotating drum, a second end 'bafl le inperipheral sealing engagement with the other end of said rota-ting drum,means supporting said second baflle for movement in the direction of thelongitudinal axis of the drum to maintain said baffle in said peripheralsealing engagement with said rotating drum as said drum expands andcontracts in length during heating and cool-ing thereof, each of saidbaffles having an inlet and an outlet separated by a center post, theinlet of one haflle positioned to be in continual communication with theoutlet Otf the other baffle through a plurality of said fluid passagesand the inlet of said other baflle positioned to be in continualcommunication with the outlet of said one baflle through a plurality ofsaid fluid pas-sages as the drum is rotated, said center postspositioned parallel to each other and each having passage means definedtherein, said passage means in one of said baffles being incommunication with the inlet thereof and a plurality of fluid passagesin said drum, said passage means in the other of ,said baffles being incommunication with the inlet thereof and a plurality of fluid passagesin said drum, and fluid passage purging means carried in each post, saidpurging means in each post positioned opposite said passage means in theother post for purging a plurality of fluid passages in said drum as thepassages pass in front of said center posts during rotation of saiddrum.

4. A regenerative heat exchanger for effecting a heat transfer betweenfluids of different temperatures, comprising a rotating drum ofregenerative material having a plurality of noncommunicating fluidpassages therein extending parallel to the axis of rotation of the drum,said drum being of substantial length whereby thermal expansion andcontraction causes appreciable changes in length, means for rotatingsaid drum, said drum having an outer steel shell and said passagesconstructed of refractory material forming an integral internalstructure supported Within said shell to rotate therewith, meansadjacent one end of said drum and restraining it against axial movement,the other end of said drum being free to move axially in response tothermal expansion and contraction of the drum, a first stationary end'baflle in peripheral sealing engagement with the restrained end of saidrotating drum, a second end fbaflle in peripheral sealing engagementwith the other end of said rotating drum, means supporting said secondbafile for movement in the directron of the axis of the drum to maintainsaid baflle in said peripheral sealing engagement with said rotatingdrum as said drum expands and contracts in length during heating andcooling thereof.

5. Apparatus as defined in claim 4 wherein the refractory materialcomprises brick shaped to form tongue and groove means between adjacentbrick for forming an integral structure.

6. A regenerative heat exchanger for effecting a heat transfer betweenfluids of different temperatures, comprising a rotating drum, said drumbeing of substantial length whereby thermal expansion and contractioncauses appreciable changes in length, means for rotating said drum,annular end flanges at the ends of said drum having radial faces,refractory means defining a plurality of separate open endedlongitudinally extending fluid passages in said drum, means adjacent oneend of said drum and restraining it against axial movement, the otherend of said drum being free to move axially in response to thermalexpansion and contraction of the drum, a first end baffle in peripheralsealing engagement with the restrained end of said drum, a second endbaffle in peripheral sealing engagement with the opposite end of saiddrum, each of said baffles having an inlet and an outlet separated by acenter post, annular end flanges on both of said baffles having radialfaces, faces on said baffles positioned to face in close proximity thefaces on the respective ends of said drum to provide said peripheralsealing engagements therewith, the inlet of said first bafile positionedto be in continual communication with the outlet of said second bafflethrough said fluid passages and the inlet of said second bafflepositioned to be in continual communication with the out-let of saidfirst baffle through said fluid passages as the drum is rotated, saidcenter posts being positioned parallel to each other and effectivelyclosing both ends of said fluid passageways.

'7. Apparatus as defined in claim 6 wherein there are provided annularseals of heat resistant material, said seals being interposed betweenthe end faces on said drum and the respective end faces on said baffles.

8. Apparatus as defined in claim 7 wherein said seals are comprised ofasbestos material and are fixedly secured to the respective end faces onsaid baffles.

9. A regenerative heat exchanger for effecting a heat transfer betweenfluids of different temperatures, comprising a rotating drum, said drumbeing of substantial length whereby thermal expansion and contractioncauses appreciable !changes in length, means for rotating said drum,refractory means defining a plurality of separate open endedlongitudinally extending fluid passages in said drum, said drum havingan outer steel shell, a fixed support base underlying said drum having aplurality of rollers mounted for rotation thereon, radially positionedannular track means secured to the exterior of said shell adjacent oneend thereof and engaging said rollers on said base for rotatablysupporting saiddrum whereby one'end of said drum is restrained againstaxial movement and the other end of said drum is free to move axially inresponse to thermal expansion and contraction of the drum, a first endbaffle in peripheral sealing engagement with the restrained end of saiddrum, a second end bafiie in sealing engagement with the opposite end'ofsaid drum, each of said baffle-s having an inlet and an outlet separatedby a center post, the inlet of said first baffle positioned to be -incontinual communication with the outlet of said second baffle throughsaid fluid passages and the inlet of said sec- 0nd baffle positioned tobe in continual communication with the outlet of said first bafflethrough said fluid passages as the drum is rotated, said center postsbeing positioned parallel to each other and effectively closing bothends of said fluid passageways.

10. Apparatus as defined in claim 9 including means for driving at leastsome of said rollers to rotate said drum.

'11. A regenerative heat exchanger for effecting heat transfer betweenfluids of. different temperatures comprising a vertically positionedrotating drum of substantiallength and including a refractory archstructure positioned in the lower end of said drum, refractory meanssupported by arch structure and defining a plurality of separateopen-ended longitudinally extending fluid passages in said drum, saiddrum having an outer steel shell, a fixed support base underlying saiddrum, a plurality of rollers positioned rotatably to support said drumupon the su port base adjacent the lower end of said drum whereby thelower end of said drum is in substantially fixed vertical position andthe upper end of said drum is free to move axially in response tothermal expansion and contraction of the drum, a lower end baffle inperipheral sealing engagement with the lower end of said drum, 2. secondend bafiie in sealing engagement with the upper end of said drum, thelower baffle having a centrally positioned wall extending therethroughin close proximity with the arch structure and dividing the lower endbaffle into inlet and outlet sections, the upper said baffle havingmeans dividing it into inlet and outlet sections, the inlet and outletsections of said upper end bafile being in continuous cornmunicationwith the outlet and inlet sections respectively of the lower end bafflethrough fi-uid passages within the drum and extending therebetween.

References Cited by the Examiner UNITED STATES PATENTS 802,151 10/ 1905Treat 26'333 1,858,508 5/1932 K-i-gnell et a1. 1654 2,789,793 4/ 1957'Ilheoilitus 165-9 3,010,703 11/1961' Bellows et a1. 1659 3,016,8931/1962 Brown 126116- FOREIGN PATENTS 1,118,388 11/1961 Germany.

FREDERICK L. MATTESON, JR., Primary Examiner.

M. A. ANTONAKAS, Assistant Examiner. f f

4. A REGENERATIVE HEAT EXCHANGER FOR EFFECTING A HEAT TRANSFER BETWEENFLUIDS OF DIFFERENT TEMPERATURES, COMPRISING A ROTATING DRUM OFREGENERATIVE MATERIAL HAVING A PLURALITY OF NONCOMMUNICATING FLUIDPASSAGES THEREIN EXTENDING PARALLEL TO THE AXIS OF ROTATING OF THE DRUM,SAID DRUM BEING OF SUBSTANTIAL LENGTH WHEREBY THERMAL EXPANSION ANDCONTRACTION CAUSES APPRECIABLE CHANGES IN LENGTH, MEANS FOR ROTATINGSAID DRUM, SAID DRUM HAVING AN OUTER STEEL SHELL AND SAID PASSAGESCONSTRUCTED OF REFRACTORY MATERIAL FORMING AN INTEGRAL INTERNALSTRUCTURE SUPPORTED WITHIN SAID SHELL TO ROTATE THEREWITH, MEANSADJACENT ONE END OF SAID DRUM AND RESTRAINING IT AGAINST AXIAL MOVEMENT,THE OTHER END OF SAID DRUM BEING FREE TO MOVE AXIALLY IN RESPONSE TOTHERMAL EXPANSION AND CONTRACTION OF THE DRUM, A FIRST STATIONARY ENDBAFFLE IN PERIPHERAL SEALING ENGAGEMENT WITH THE RESTRAINED END OF SAIDROTATING DRUM, A SECOND END BAFFLE IN PERIPHERAL SEALING ENGAGEMENT WITHTHE OTHER END OF SAID ROTATING DRUM, MEANS SUPPORTING SAID SECOND BAFFLEFOR MOVEMENT IN THE DIRECTION OF THE AXIS OF THE DRUM TO MAINTAIN SAIDBAFFLE IN SAID PERIPHERAL SEALING ENGAGEMENT WITH SAID ROTATING DRUM ASSAID DRUM EXPANDS AND CONTRACTS IN LENGTH DURING HEATING AND COOLINGTHEREOF.